Image Output Filetype for Compositing
Use OpenEXR multilayer.



Think of EXR as a perfect copy of the render layers. Multilayer will allow you to save all of the different passes.

EXR will keep your information linear and un-distorted by color transforms, with the proper associated alpha channel and the z pass as unbound data.

Enable the render passes that you want in the view layer.



Use a File Output node, create as many layers as you need with the Add input button. Then plug the output sockets of each of the render layers you want to save.



Png is a terrible format, never meant for compositing.